Molecular cloning of the rat IL-13 alpha 2 receptor cDNA and its expression in rat tissues

The interleukin 13 alpha 2 receptor (IL-13Ralpha2) is highly expressed in human glioma cells. As a consequence this receptor has been proposed as a potential target for immunotherapeutic approaches for treating brain tumors. In developing animal models that may utilize the IL-13Ralpha2 receptor as an immunotherapeutic target, only the murine gene sequence has thus far been elucidated. The purpose of the present study, therefore, was to determine the gene sequence and tissue distribution of IL-13Ralpha2 in the rat. A search of the NCBI expressed sequence tag (EST) database with human and mouse IL-13Ralpha2 gene sequences identified a rat EST with high homology to the human and mouse IL-13Ralpha2 conserved region. Based on the sequence information, a 1917 bp rat IL-13Ralpha2 cDNA was cloned using the 5' and 3' RACE PCR technique. The cloned rat IL-13Ralpha2 cDNA contains a full-length 1158 bp open reading frame. The deduced protein is 91.2% and 54.2% homologous to mouse and human IL- 13Ralpha2, respectively, at the amino acid level. Analysis shows that the rat IL-13Ralpha2 is structurally conserved and similar to human and mouse. It has a very short cytoplasmic domain, an extracellular domain containing an N-terminal fibronectin type III domain, four putative N-glycosylation sites, and a growth factor and cytokine receptor family motif WSEWS. Using RT-PCR techniques, the mRNA of rat IL-13Ralpha2 was detected in rat brain, spleen, liver, thymus, stomach, testis, and three rat glioblastoma cell lines C6, A15A5 and 9L. The cloning of rat IL-13Ralpha2 may be helpful to establish a rat model for IL-13Ralpha2 related glioma therapies.